Multi-RPO data protection

ABSTRACT

A system for disaster recovery including a controller (i) for controlling bandwidth usage of a disaster recovery system in accordance with a plurality of recovery point objectives (RPOs), each RPO designating a maximal time loss constraint for data recovery for an enterprise production system, and a corresponding bandwidth allocation for the disaster recovery system to use in replicating data for the enterprise production system, wherein the RPOs are applied in accordance with a calendar-based schedule of dates and times, and (ii) for issuing an RPO alert when the RPO maximal time loss constraint for a current date and time is not satisfied.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.13/175,898, entitled METHODS AND APPARATUS FOR PROVIDING HYPERVISORLEVEL DATA SERVICES FOR SERVER VIRTUALIZATION, filed on Jul. 4, 2011 byinventors Ziv Kedem, Gil Levonai, Yair Kuszpet and Chen Burshan, whichis a continuation-in-part of U.S. application Ser. No. 13/039,446,entitled METHODS AND APPARATUS FOR PROVIDING HYPERVISOR LEVEL DATASERVICES FOR SERVER VIRTUALIZATION, filed on Mar. 3, 2011 by inventorZiv Kedem, which claims priority benefit of U.S. Provisional ApplicationNo. 61/314,589, entitled METHODS AND APPARATUS FOR PROVIDING HYPERVISORLEVEL DATA SERVICES FOR SERVER VIRTUALIZATION, filed on Mar. 17, 2010 byinventor Ziv Kedem.

FIELD OF THE INVENTION

The present invention relates to data protection.

BACKGROUND OF THE INVENTION

Data is at the heart of every enterprise, and a core component of datacenter infrastructure. As data applications become more and morecritical, there is a growing need to ensure complete businesscontinuity.

Disaster recovery systems provide data protection and applicationrecovery. Some disaster recovery systems use virtual data replicationwithin a hypervisor architecture, and are able to recover any point intime.

Objectives of disaster recovery plans are generally formulated in termsof recovery point objective (RPO) and recovery time objective (RTO).

RPO is a point in time to which data must be recovered. RPO indicates anamount of data that an enterprise determines is an acceptable loss in adisaster situation. RPO allows an enterprise to define a window of timebefore a disaster during which data may be lost. The value of the datain this window of time may be weighed against the cost of the additionaldisaster prevention measures that would be necessary to shorten thewindow.

RTO is the time it takes to get a non-functional system back on-line,and indicates how fast the enterprise will be up and running after adisaster. Specifically, RTO is the duration of time within which abusiness process must be restored after a disaster, in order to avoidunacceptable consequences associated with a break in businesscontinuity. Most disaster recovery systems provide RTOs on the order ofseveral hours.

RPO is independent of RTO. If the RPO of an enterprise is two hours,then when a system is brought back on-line after a disaster, all datamust be restored to a point within two hours before the disaster. Butthe enterprise has acknowledged that data in the two hours immediatelypreceding the disaster may be lost; i.e., the acceptable loss window istwo hours.

Conventional disaster recovery systems are single-RPO systems; i.e., asingle RPO objective applies. In this regard, reference is made to FIG.1, which is a screen shot of a prior art single-RPO console for adisaster recovery application. As shown in FIG. 1, a single RPOobjective designates an RPO threshold time of 2 minutes, and amaintenance history of 4 hours.

An enterprise may share its overall bandwidth between its actualproduction system, and its disaster recovery system. A RPO may becontrolled by the amount of bandwidth of the overall enterprise systemallocated to the disaster recovery system. By allocating more bandwidthto the disaster recovery system, the RPO may be improved to reduce thewindow of data loss in case of disaster, but less bandwidth is thenavailable for the enterprise production system. Conversely, byallocating less bandwidth to the disaster recovery system, the RPO isdegraded to increase the window of data loss in case of disaster, andmore bandwidth is then available for the enterprise production system.

When a disaster recovery system falls short of its RPO objective, itissues an RPO alert. If an administrator receives a series of RPOalerts, it generally means that the bandwidth allocated to the disasterrecovery system is insufficient for the RPO objective, and the RPOobjective must be relaxed or additional bandwidth must be allocated.Generally, allocating additional bandwidth to the disaster recoverysystem entails the expense of obtaining additional bandwidth for theoverall enterprise system, in order not to degrade the enterpriseproduction system.

Enterprise production systems generate data at varying rates, accordingto peaks times and off-peak times. Peak times and off-peak times may bedifferent for different applications. E.g., a customer relationshipmanagement (CRM) application may have peak times during normal workinghours and off-peak times during nights and weekends, whereas a fast-foodordering system may have peak hours during nights and weekends.Maintaining a low RPO at all times requires a WAN link with a bandwidththat accommodates the peak rates. Such lines are expensive, and arefully utilized only during relatively short time periods.

Cloud service disaster recovery systems support multiple enterprises.Maintaining high bandwidth lines for all enterprises is expensive, anddoes not fully utilize the lines most of the time. Reducing thebandwidth results in system alerts when the RPO is exceeded—alerts thatthe system administrator wants to avoid. Increasing the RPO results inmissing alerts that should be issued.

It would thus be of advantage to enable a disaster recovery system todesignate different RPO objectives based on the day and the time of day,with different respective bandwidths allocated to the disaster recoverysystem.

SUMMARY OF THE DESCRIPTION

Aspects of the present invention overcome drawbacks with conventionalsingle-RPO disaster recovery systems, and provide multi-RPO disasterrecovery systems, for designating multiple RPO objectives based on dayand time of day, with multiple respective bandwidths allocated to thedisaster recovery systems. Aspects of the present invention providedisaster recovery systems with calendar-based, or date and time-based,RPO objectives and bandwidth allocations, thereby achieving greaterflexibility and cost effectiveness vis-à-vis conventional single-RPOsystems.

Using the present invention, a disaster recovery system may share a linkbetween sites for replication and applications. The disaster recoverysystem may set a higher RPO objective during peak times and a lower RPOobjective during off-peal times, limit replication bandwidth during peaktimes, and relax replication bandwidth during off-peak times. Thedisaster recovery system may use the different RPO objectives toadvantage for allowing as much bandwidth as possible, taking intoaccount that a higher RPO objective is met during peak times, whilecatching up afterwards during off-peak times when the RPO objective islower.

Conversely, the disaster recovery system may set a lower RPO objectiveduring peak times and a higher RPO objective during off-peak times, toenable sharing the link with other systems during off-peak times.

In accordance with an embodiment of the present invention, a controlelement is installed, to control bandwidth at a site level, protectiongroup level. The control element monitors RPO objective andcorresponding allocated bandwidth in accordance with a calendar-based,or a date and time-based schedule.

In accordance with an embodiment of the present invention, a disasterrecovery system may set different limits for data seeding traffic vs.data replication traffic over a WAN.

There is thus provided in accordance with an embodiment of the presentinvention a system for disaster recovery including a controller (i) forcontrolling bandwidth usage of a disaster recovery system in accordancewith a plurality of recovery point objectives (RPOs), each RPOdesignating a maximal time loss constraint for data recovery for anenterprise production system, and a corresponding bandwidth allocationfor the disaster recovery system to use in replicating data for theenterprise production system, wherein the RPOs are applied in accordancewith a calendar-based schedule of dates and times, and (ii) for issuingan RPO alert when the RPO maximal time loss constraint for a currentdate and time is not satisfied.

There is additionally provided in accordance with an embodiment of thepresent invention a method for disaster recovery, including accessing acalendar-based schedule of recovery point objectives (RPOs) andcorresponding bandwidth allocations for a disaster recovery system, eachRPO designating a maximal time loss constraint for data recovery for anenterprise production system, and each bandwidth allocation constrainingbandwidth usage for replicating data for the enterprise productionsystem, retrieving, by the disaster recovery system at any given dateand time, the recovery point objective (RPO) and the correspondingbandwidth allocation for the given date and time, from thecalendar-based schedule, limiting, by the disaster recovery system atthe given date and time, bandwidth usage of the disaster recovery systemin accordance with the retrieved bandwidth allocation, determining, bythe disaster recovery system, a current RPO, and if the current RPOexceeds the retrieved RPO, then issuing, by the disaster recoverysystem, an RPO alert.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood and appreciated fromthe following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a screen shot of a prior art single-RPO console for a disasterrecovery application;

FIG. 2 is a simplified block diagram of a hypervisor architecture thatincludes a tapping driver and a virtual data services appliance, inaccordance with an embodiment of the present invention;

FIG. 3 is a simplified data flow chart for a virtual data servicesappliance, in accordance with an embodiment of the present invention;

FIG. 4 is a simplified block diagram of a virtual replication system, inaccordance with an embodiment of the present invention;

FIG. 5 is a simplified block diagram of a cross-host multiple hypervisorsystem that includes data services managers for multiple sites that havemultiple hypervisors, in accordance with an embodiment of the presentinvention;

FIG. 6 is a user interface screenshot of bi-directional replication ofvirtual protection groups, in accordance with an embodiment of thepresent invention;

FIG. 7 is a user interface screenshot of assignment of a replicationtarget for a virtual protection group, in accordance with an embodimentof the present invention;

FIG. 8 is an example an environment for the system of FIG. 4, inaccordance with an embodiment of the present invention;

FIG. 9 is a simplified block diagram of a system for multi-tenant andmulti-site cloud-based data services, in accordance with an embodimentof the present invention;

FIG. 10 is a simplified block diagram of a first architecture forproviding hypervisor level mufti-tenant cloud-based data services, inaccordance with an embodiment of the present invention;

FIG. 11 is a simplified block diagram of a second architecture forproviding hypervisor level mufti-tenant cloud-based data services, inaccordance with an embodiment of the present invention;

FIG. 12 is a simplified block diagram of a third architecture forproviding hypervisor level mufti-tenant cloud-based data services, inaccordance with an embodiment of the present invention;

FIG. 13 is a simplified block diagram of a fourth architecture forproviding hypervisor level mufti-tenant cloud-based data services, inaccordance with an embodiment of the present invention;

FIG. 14 is a simplified block diagram of a system for multi-tenant andmufti-site cloud-based data services with jurisdictional dataseparation, in accordance with an embodiment of the present invention;

FIG. 15 is a screen shot of a mufti-RPO console for a disaster recoveryapplication, in accordance with an embodiment of the present invention;

FIG. 16 is a simplified block diagram of an exemplary mufti-RPO dataprotection system, in accordance with an embodiment of the presentinvention; and

FIG. 17 is a simplified flow diagram of a method for multi-RPO dataprotection, in accordance with an embodiment of the present invention.

LIST OF APPENDICES

Appendix I is an application programming interface for virtualreplication site controller web services, in accordance with anembodiment of the present invention;

Appendix II is an application programming interface for virtualreplication host controller web services, in accordance with anembodiment of the present invention;

Appendix III is an application programming interface for virtualreplication protection group controller web services, in accordance withan embodiment of the present invention;

Appendix IV is an application programming interface for virtualreplication command tracker web services, in accordance with anembodiment of the present invention; and

Appendix V is an application programming interface for virtualreplication log collector web services, in accordance with an embodimentof the present invention.

DETAILED DESCRIPTION

Aspects of the present invention relate to disaster recovery withmultiple RPOs that are applied in accordance with a schedule of datesand times.

Reference is made to FIG. 2, which is a simplified block diagram of ahypervisor architecture that includes a tapping driver and a VDSA, inaccordance with an embodiment of the present invention. Shown in FIG. 2is a hypervisor 100 with three virtual servers 110, three virtual disks120, an I/O backend 130 and a physical storage array 140. Hypervisor 100uses a single physical server, but runs multiple virtual servers 110.Virtual disks 120 are a storage emulation layer that provide storage forvirtual servers 110. Virtual disks 120 are implemented by hypervisor 100via I/O backend 130, which connects to physical disk 140.

Hypervisor 100 also includes a tapping driver 150 installed within thehypervisor kernel. As shown in FIG. 2, tapping driver 150 resides in asoftware layer between virtual servers 110 and virtual disks 120. Assuch, tapping driver 150 is able to access I/O requests performed byvirtual servers 110 on virtual disks 120. Tapping driver 150 hasvisibility to I/O requests made by virtual servers 110.

Hypervisor 100 also includes a VDSA 160. In accordance with anembodiment of the present invention, a VDSA 160 runs on a separatevirtual server within each physical hypervisor. VDSA 160 is a dedicatedvirtual server that provides data services via one or more data servicesengines 170. However, VDSA 160 does not reside in the actual I/O datapath between I/O backend 130 and physical disk 140. Instead, VDSA 160resides in a virtual I/O data path.

Whenever a virtual server 110 performs I/O on a virtual disk 120,tapping driver 150 identifies the I/O requests that the virtual servermakes. Tapping driver 150 copies the I/O requests, forwards one copy viathe conventional path to I/O backend 130, and forwards another copy toVDSA 160. In turn, VDSA 160 enables the one or more data servicesengines 170 to provide data services based on these I/O requests.

Reference is made to FIG. 3, which is a simplified data flow chart for aVDSA, in accordance with an embodiment of the present invention. Shownin FIG. 3 are an I/O receiver 210, a hash generator 220, a TCPtransmitter 230, a data analyzer and reporter 240, a journal manager 250and a remote VDSA 260. Remote VDSA 260 resides on different physicalhardware, at a possibly different location.

As shown in FIG. 3, I/O receiver 210 receives an intercepted I/O requestfrom tapping driver 150. VDSA 160 makes up to three copies of thereceived I/O requests, in order to perform a set of actions which enablethe one or more data services engines 170 to provide various services.

A first copy is stored in persistent storage, and used to providecontinuous data protection. Specifically, VDSA 160 sends the first copyto journal manager 250, for storage in a dedicated virtual disk 270.Since all I/O requests are journaled on virtual disk 270, journalmanager 250 provides recovery data services for virtual servers 110,such as restoring virtual servers 110 to an historical image. In orderto conserve disk space, hash generator 220 derives a one-way hash fromthe I/O requests. Use of a hash ensures that only a single copy of anyI/O request data is stored on disk.

An optional second copy is used for disaster recovery. It is sent viaTCP transmitter 230 to remote VDSA 260. As such, access to all data isensured even when the production hardware is not available, thusenabling disaster recovery data services.

An optional third copy is sent to data analyzer and reporter 240, whichgenerates a report with information about the content of the data. Dataanalyzer and reporter 240 analyzes data content of the I/O requests andinfers information regarding the data state of virtual servers 110.E.g., data analyzer and reporter 240 may infer the operating systemlevel and the status of a virtual server 110.

Reference is made to FIG. 4, which is a simplified block diagram of avirtual replication system, in accordance with an embodiment of thepresent invention. Shown in FIG. 4 is a protected site designated SiteA, and a recovery site designated Site B. Site A includes a hypervisor100A with three virtual servers 110A-1, 110A-2 and 110A-3, and a VDSA160A. Site A includes two physical disks 140A-1 and 140A-2. Site Bincludes a hypervisor 100B with a VDSA 160B. Site B includes twophysical disks 140B-1 and 140B-2. All or some of virtual servers 110A-1,110A-2 and 110A-3 may be designated as protected. Once a virtual serveris designated as protected, all changes made on the virtual server arereplicated at the recovery site.

In accordance with an embodiment of the present invention, every writecommand from a protected virtual server in hypervisor 100A isintercepted by tapping driver 150 (FIG. 2) and sent asynchronously byVDSA 160A to VDSA 160B for replication, via a wide area network (WAN)320, while the write command continues to be processed by the protectedserver.

At Site B, the write command is passed to a journal manager 250 (FIG.3), for journaling on a Site B virtual disk 270 (FIG. 3). After everyfew seconds, a checkpoint is written to the Site B journal, and during arecovery one of the checkpoints may be selected for recovering to thatpoint. Additionally, checkpoints may be manually added to the Site Bjournal by an administrator, along with a description of the checkpoint.E.g., a checkpoint may be added immediately prior to an event takingplace that may result in the need to perform a recovery, such as aplanned switch over to an emergency generator.

In addition to write commands being written to the Site B journal,mirrors 110B-1, 110B-2 and 110B-3 of the respective protected virtualservers 110A-1, 110A-2 and 110A-3 at Site A are created at Site B. Themirrors at Site B are updated at each checkpoint, so that they aremirrors of the corresponding virtual servers at Site A at the point ofthe last checkpoint. During a failover, an administrator can specifythat he wants to recover the virtual servers using the latest data sentfrom the Site A. Alternatively the administrator can specify an earliercheckpoint, in which case the mirrors on the virtual servers 110B-1,110-B-2 and 110B-3 are rolled back to the earlier checkpoint, and thenthe virtual servers are recovered to Site B. As such, the administratorcan recover the environment to the point before any corruption, such asa crash or a virus, occurred, and ignore the write commands in thejournal that were corrupted.

VDSAs 160A and 160B ensure write order fidelity; i.e., data at Site B ismaintained in the same sequence as it was written at Site A. Writecommands are kept in sequence by assigning a tinnestanrip or a sequencenumber to each write at Site A. The write commands are sequenced at SiteA, then transmitted to Site B asynchronously, then reordered at Site Bto the proper time sequence, and then written to the Site B journal.

The journal file is cyclic; i.e., after a pre-designated time period,the earliest entries in the journal are overwritten by the newestentries.

It will be appreciated by those skilled in the art that the virtualreplication appliance of the present invention operates at thehypervisor level, and thus obviates the need to consider physical disks.In distinction, conventional replication systems operate at the physicaldisk level. Embodiments of the present invention recover write commandsat the application level. Conventional replication systems recover writecommands at the SCSI level. As such, conventional replication systemsare not fully application-aware, whereas embodiment of the presentinvention are full application-aware, and replicate write commands froman application in a consistent manner.

The present invention offers many advantages.

-   -   Hardware Agnostic: Because VDSA 160 manages recovery of virtual        servers and virtual disks, it is not tied to specific hardware        that is used at the protected site or at the recovery site. The        hardware may be from the same vendor, or from different vendors.        As long as the storage device supports the iSCSI protocol, any        storage device, known today or to be developed in the future,        can be used.    -   Fully Scalable: Because VDSA 160 resides in the hypervisor        level, architectures of the present invention scale to multiple        sites having multiple hypervisors, as described hereinbelow with        reference to FIG. 5.    -   Efficient Asynchronous Replication: Write commands are captured        by VDSA 160 before they are written to a physical disk at the        protected site. The write commands are sent to the recovery site        asynchronously, and thus avoid long distance replication        latency. Moreover, only delta changes are sent to the recovery        site, and not a whole file or disk, which reduces the network        traffic, thereby reducing WAN requirements and improving        recovery time objective and recovery point objective.    -   Control of Recovery: An administrator controls when a recovery        is initiated, and to what point in time it recovers.    -   Near-Zero Recovery Point Objective (RPO): VDSA 160 continuously        protects data, sending a record of every write command        transacted at the protected site to the recovery site. As such,        recovery may be performed within a requested RPO.    -   Near-Zero Recovery Time Objective (RTO): During recovery the        mirrors of the protected virtual servers are recovered at the        recovery site from VDSA 160B, and synchronized to a requested        checkpoint. In accordance with an embodiment of the present        invention, during synchronization and while the virtual servers        at the recovery site are not yet fully synchronized, users can        nevertheless access the virtual servers at the recovery site.        Each user request to a virtual server is analyzed, and a        response is returned either from the virtual server directly, or        from the journal if the information in the journal is more        up-to-date. Such analysis of user requests continues until the        recovery site virtual environment is fully synchronized.    -   WAN Optimization between Protected and Recovery Sites: In        accordance with an embodiment of the present invention, write        commands re compressed before being sent from VDSA 160A to VDSA        160B, with throwing used to prioritize network traffic. As such,        communication between the protected site and the recovery site        is optimized.    -   WAN Failover Resilience: In accordance with an embodiment of the        present invention, data is cached prior to being transmitted to        the recovery site. If WAN 320 goes down, the cached data is        saved and, as soon as WAN 320 comes up again, the data is sent        to the recovery site and both sites are re-synchronized.    -   Single Point of Control: In accordance with an embodiment of the        present invention, both the protected and the recovery site are        managed from the same client console.    -   Secure Multi-Tenant Solution on Shared Hardware: The present        invention enables multiple enterprises to use shared hardware at        a recovery site for data replication, while maintaining security        between the enterprises, as described hereinbelow with reference        to FIGS. 10-13.

As indicated hereinabove, the architecture of FIG. 2 scales to multiplesites having multiple hypervisors. Reference is made to FIG. 5, which isa simplified block diagram of a cross-host multiple hypervisor system300 that includes data services managers for multiple sites that havemultiple hypervisors, in accordance with an embodiment of the presentinvention. The architecture of FIG. 5 includes three sites, designatedSite A, Site B and Site C, the three sites being communicatively coupledvia a network 320. Each site includes one or more hypervisors 100.Specifically, Site A includes three hypervisors, 100A/1, 100A/2 and100A/3, Site B includes two hypervisors, 100B/1 and 100B/2, and Site Cincludes one hypervisor 100C/1. The sites have respective one or morephysical disks 140A, 140B and 140C.

The hypervisors are shown in system 300 with their respective VDSA's160A/1, 160A/2, . . . , and the other components of the hypervisors,such as the virtual servers 110 and virtual disks 120, are not shown forthe sake of clarity. An example system with virtual servers 110 is shownin FIG. 8, and described hereinbelow.

The sites include respective data services managers 310A, 310B and 310Cthat coordinate hypervisors in the sites, and coordinate hypervisorsacross the sites.

The system of FIG. 5 may be used for data replication, whereby data atone site is replicated at one or more other sites, for protection. Thesolid communication lines 330 in FIG. 5 are used for in-site traffic,the dashed communication lines 340 are used for replication trafficbetween sites, and the dotted communication lines 350 are used forcontrol traffic between data services managers.

Data services managers 310A, 310B and 310C are control elements. Thedata services managers at each site communicate with one another tocoordinate state and instructions. The data services managers track thehypervisors in the environment, and track health and status of the VDSAs160A/1, 160A/2, . . . .

It will be appreciated by those skilled in the art that the environmentshown in FIG. 5 may be re-configured by moving one or more virtualservers 110 from one hypervisor 100 to another, by moving one or morevirtual disks 120 from one hypervisor 100 to another, and by adding oneor more additional virtual servers 110 to a hypervisor 100.

In accordance with an embodiment of the present invention, the dataservices managers enable designating groups of specific virtual servers110, referred to as virtual protection groups, to be protected. Forvirtual protection groups, write order fidelity is maintained. The dataservices managers enable designating a replication target for eachvirtual protection group; i.e., one or more sites, and one or morehypervisors in the one or more sites, at which the virtual protectiongroup is replicated. A virtual protection group may have more than onereplication target. The number of hypervisors and virtual servers withina virtual protection group and its replication target are not requiredto be the same.

Reference is made to FIG. 6, which is a user interface screenshot ofbi-directional replication of virtual protection groups, in accordancewith an embodiment of the present invention. Shown in FIG. 4 are virtualprotection groups 301 (“Exchange”), 302 (“WebApp”), 303 (“Dummy-R1”),304 (“Windows 2003”) and 305 (Dummies-L”). Arrows 306 indicate directionof replication.

Reference is made to FIG. 7, which is a user interface screenshot ofassignment of a replication target for a virtual protection group, inaccordance with an embodiment of the present invention. Shown in FIG. 7is an entry 307 for designating a recovery host, and an entry 308 fordesignating a recovery datastore for virtual protection group 304(“Windows 2003”) of FIG. 6. Respective source and target datastores,[SAN ZeRTO-30] 309A and [datastore1] 309B, are shown as being paired.

More generally, the recovery host may be assigned to a cluster, insteadof to a single hypervisor, and the recovery datastore may be assigned toa pool of resources, instead of to a single datastore. Such assignmentsare of particular advantage when different enterprises share the samephysical infrastructure for target replication, as such assignments maskthe virtual infrastructure between the different enterprises.

The data services managers synchronize site topology information. Assuch, a target site's hypervisors and datastores may be configured froma source site.

Virtual protection groups enable protection of applications that run onmultiple virtual servers and disks as a single unit. E.g., anapplication that runs on virtual servers many require a web server and adatabase, each of which run on a different virtual server than thevirtual server that runs the application. These virtual servers may bebundled together using a virtual protection group.

Referring back to FIG. 5, data services managers 310A, 310B and 310Cmonitor changes in the environment, and automatically update virtualprotection group settings accordingly. Such changes in the environmentinclude inter alia moving a virtual server 110 from one hypervisor 100to another, moving a virtual disk 120 from one hypervisor 100 toanother, and adding a virtual server 110 to a hypervisor 100.

For each virtual server 110 and its target host, each VDSA 160A/1,160A/2, . . . replicates IOs to its corresponding replication target.The VDSA can replicate all virtual servers to the same hypervisor, or todifferent hypervisors. Each VDSA maintains write order fidelity for theIOs passing through it, and the data services manager coordinates thewrites among the VDSAs.

Since the replication target hypervisor for each virtual server 110 in avirtual protection group may be specified arbitrarily, all virtualservers 110 in the virtual protection group may be replicated at asingle hypervisor, or at multiple hypervisors. Moreover, the virtualservers 110 in the source site may migrate across hosts duringreplication, and the data services manager tracks the migration andaccounts for it seamlessly.

Reference is made to FIG. 8, which is an example an environment forsystem 300, in accordance with an embodiment of the present invention.As shown in FIG. 8, system 300 includes the following components.

Site A

-   Hypervisor 100A/1: virtual servers 110A/1-1, 110A/1-2, 110A/1-3.-   Hypervisor 100A/2: virtual servers 110A/2-1, 110A/2-2, 110A/2-3.-   Hypervisor 100A/3: virtual servers 110A/3-1, 110A/3-2, 110A/3-3.    Site B-   Hypervisor 100B/1: virtual servers 110B/1-1, 110B/1-2, 110B/1-3.-   Hypervisor 100B/2: virtual servers 110B/2-1, 110B/2-2, 110B/2-3.    Site C-   Hypervisor 100C/1: virtual servers 110C/1-1, 110C/1-2, 110C/1-3,    110C/1-4.

As further shown in FIG. 8, system 300 includes the following virtualprotection groups. Each virtual protection group is shown with adifferent hatching, for clarity.

VPG1 (Shown with Upward-sloping Hatching)

-   -   Source at Site A: virtual servers 110A/1-1, 110A/2-1, 110A/3-1    -   Replication Target at Site B: virtual servers 110B/1-1,        110B/1-2, 110B/2-1        VPG2 (Shown with Downward-sloping Hatching)    -   Source at Site B: virtual servers 110B/1-3, 110B/2-2    -   Replication Target at Site A: virtual servers 110A/1-2, 110A/2-2        VPG3 (Shown with Horizontal Hatching)    -   Source at Site A: virtual server 110A/3-3    -   Replication Target at Site B: virtual serer 110B/2-3    -   Replication Target at Site C: virtual server 110C/1-4        VPG4 (Shown with Vertical Hatching)    -   Source at Site A: virtual servers 110A/1-3, 110A/2-3, 110A/3-2    -   Replication Target at Site C: virtual servers 110C/1-1,        110C/1-2, 110C/1-3

As such, it will be appreciated by those skilled in the art that thehypervisor architecture of FIG. 2 scales to multiple host sites, each ofwhich hosts multiple hypervisors. The scaling flexibly allows fordifferent numbers of hypervisors at different sites, and differentnumbers of virtual services and virtual disks within differenthypervisors.

The scaling flexibility of the present invention also allows extensionto cloud-based data services provided by a cloud provider on a sharedinfrastructure, as explained hereinbelow.

Cloud-based data services enable data center providers to servicemultiple enterprises at data centers that are remote from theenterprises. Cloud-based data services offer many advantages.Enterprises that use cloud-based data services obviate the needs forservers, SAN/NAS, networks, communication lines, installation,configuration and ongoing maintenance of information technology systems,and overhead expenses for electricity, cooling and space. However,conventional cloud-based data suffer from weakness of security due tomultiple enterprises sharing the same physical infrastructure, and dueto multiple enterprises using the same networks and IPs for theirservices.

Cloud-based systems of the present invention overcome these weaknesses.Reference is made to FIG. 9, which is a simplified block diagram of asystem 500 for mufti-tenant and mufti-site cloud-based data services, inaccordance with an embodiment of the present invention. Shown in FIG. 9are three enterprises, designated A, B and C, and a remote cloud-basedfacility 490 with two data centers, designated 1 and 2. Enterprise Auses a NETAPP® data management system, Enterprise B uses an IBM® datamanagement system, and Enterprise C uses an EMC²® data managementsystem. Data Center 1 uses an EMC²® data management system and servicesEnterprise A. Data Center 2 uses a NETAPP® data management system andservices Enterprises B and C.

System 500 has many advantages over conventional data service systems.Inter alia, system 500 enables protection of heterogenic environments,enables remote control of enterprise sites, enables economies of scale,enables complete workload mobility, enables a complete web services APIfor seamless integration, and enables integration with other cloud-basedmanagement systems.

Reference is made to FIG. 10, which is a simplified block diagram of afirst architecture of system 500 for providing hypervisor levelmufti-tenant cloud-based data services, in accordance with an embodimentof the present invention. The architecture shown in FIG. 10 includes twoenterprises; namely, a smaller enterprise A and a larger enterprise B.Enterprise A infrastructure includes a single hypervisor 100A/1 withfive virtual servers 100A/1-1, 100A/1-2, 100A/1-3, 100A/1-4 and 100A/1-5and a VDSA 160A/1, includes two physical disks 120A-1 and 120A-2, andincludes a data services manager 310A. Enterprise B infrastructureincludes two hypervisors 100B/1 and 100B/2, includes three physicaldisks 120B-1, 120B-2 and 120B-3, and a data services manager 310B.Hypervisor 100B/1 includes five virtual servers 100B/1-1, 100B/1-2,100B/1-3, 100B/1-4 and 100B/1-5 and a VDSA 160B/1; and hypervisor 100B/2includes five virtual servers 100B/2-1, 100B/2-2, 100B/2-3, 100B/2-4 and100B/2-5 and a VDSA 160B/2.

Cloud-based facility 490 infrastructure includes two hypervisors 400/1and 400/2, and four physical disks 420-1, 420-2, 420-3 and 420-4.Hypervisor 400/1 includes six virtual servers 410/1-1, 410/1-2, 410/1-3,410/1-4, 410/1-5 and 410/1-6; and hypervisor 400/2 includes two virtualservers 410/2-1 and 410/2-2. Hypervisor 400/1 services Enterprises A andB, and hypervisor 400/2 services Enterprise B. As such, theinfrastructure of cloud-based facility 490 is shared between EnterprisesA and B.

The architecture of FIG. 10 allocates one data services manager perenterprise and one VDSA per hypervisor. Specifically, hypervisor 400/1includes a VDSA 460/1 and hypervisor 400/2 includes a VDSA 460/2. A dataservices manager 510A services Enterprise A, and a data services manager5108 services Enterprise B.

Reference is made to FIG. 11, which is a simplified block diagram of asecond architecture of system 500 for providing hypervisor levelmufti-tenant cloud-based data services, in accordance with an embodimentof the present invention. The architecture of FIG. 11 allocates one dataservices manager per enterprise and one VDSA per enterprise perhypervisor. Specifically, hypervisor 400/1 includes a VDSA 460A/1 forEnterprise A and a VDSA 460B/1 for Enterprise B, and hypervisor 400/2includes a VDSA 460B/2 for Enterprise B.

Reference is made to FIG. 12, which is a simplified block diagram of athird architecture of system 500 for providing hypervisor levelmufti-tenant cloud-based data services, in accordance with an embodimentof the present invention. The architecture of FIG. 12 allocates one dataservices manager in the cloud, and one VDSA per hypervisor. In addition,one enterprise connector is allocated per enterprise. Specifically, aconnector 480A is allocated to Enterprise A, and a connector 480B isallocated to Enterprise B. Connector 480A is connected to both VDSA460/1 and VDSA 460/2 and to a cloud data services manager 510 on thecloud side, and is connected to Enterprise A data services manager 310Aand VDSA 160A/1 on the enterprise side. Similarly, connector 480B isconnected to VDSA 460/1, VDSA 460/2 and cloud data services manager 510on the cloud side, and is connected to Enterprise B data servicesmanager 310B, VDSA 1608/1 and VDSA 160B/2 on the enterprise side. Assuch, each enterprise is connected to the entire infrastructure on thecloud side via its own connector.

Reference is made to FIG. 13, which is a simplified block diagram of afourth architecture of system 500 for providing hypervisor levelmufti-tenant cloud-based data services, in accordance with an embodimentof the present invention. The architecture of FIG. 13 also allocates onedata services manager in the cloud, and one VDSA per hypervisor. Inaddition, one enterprise connector is allocated per enterprise.Connectors 480A and 480B on the cloud side are paired with respectiveconnectors 380A and 380B on the enterprise side. Use of connectors 380Aand 380B eliminates the need for a virtual private network (VPN), andenables installation of system 500 behind network address translators(NATs).

The different architectures in FIGS. 10-13 offer different advantages.The architecture of FIG. 10 minimizes the cloud footprint of the VDSA,by using a shared VDSA per hypervisor, and only one data servicesmanager per enterprise. Specifically, the VDSA is shared betweenenterprises and security is enforced via the data services managers. Inthis architecture, the data services manager is duplicated perenterprise and centralized cloud management is lacking.

The architecture of FIG. 11 maximizes data path security forenterprises, but the cloud footprint is larger, since multiple dataservices managers may be required per hypervisor.

The architectures of FIGS. 12 and 13 provides data security, networksecurity, minimal cloud footprint, and single point of control for cloudvendors. In this architecture, there is only one centralized dataservice manager on the cloud side, and only one VDSA per hypervisor. Onecloud connector element is deployed on the cloud side, per enterprise.The cloud connector securely routes enterprise traffic from theenterprise network to the cloud infrastructure replication network, thusproviding full network security and deployment features, including interalia duplicate IP range utilization for different enterprises whilemaintaining unique network deployment on the cloud infrastructure side.The data services manager and VDSA's perform secure site authenticationand data security, for end-to-end secure multi-tenant service.

As such, it will be appreciated by those skilled in the art that thecloud-based hypervisor level data services systems of the presentinvention enable multi-tenancy and multi-site services. I.e., multipleenterprises and multiple sites may be serviced by the same physicalinfrastructure including inter alia the same hypervisors and storage,with minimized footprint on the cloud side, allowing for centralizedcloud management. By providing each enterprise with its own dataservices manager on the clod side, as in FIGS. 10 and 11, oralternatively with its own connector and a centralized data servicesmanager on the cloud side, as in FIGS. 12 and 13, the systems of thepresent invention provide path separation between enterprises, thusensuring that each enterprise is only able to view and access his ownvirtual servers and storage, and each enterprise can only control itsown data replication.

By deploying additional cloud connectors on the enterprise side, as inFIG. 13, the systems of the present invention may be installed behindNATs, and do not require a VPN. As such, these systems may obviate VPNsetups for enterprises, and obviate use of dedicated public IPs. Foradditional security, the cloud connectors encrypt traffic, thuseliminating the need for additional network security elements.

The systems of the present invention provide bi-directional cloud-baseddata replication services; i.e., from an enterprise to the cloud, andfrom the cloud to an enterprise, for the same enterprise or fordifferent enterprises, simultaneously using the same sharedinfrastructure. Moreover, replication targets may be set as resourcesthat do not expose the enterprise infrastructure, thus providing anadditional layer of security and privacy between enterprises.

It will be appreciated by those skilled in the art that systems of thepresent invention may be used to enforce jurisdictional data exportregulations. Specifically, cloud-based facility 490 infrastructure ispartitioned according to jurisdictions, and data recovery and failoverfor an enterprise is limited to one or more specific partitionsaccording to jurisdictional regulations.

Reference is made to FIG. 14, which is a simplified block diagram of asystem 600 for mufti-tenant and mufti-site cloud-based data serviceswith jurisdictional data separation, in accordance with an embodiment ofthe present invention. Shown in FIG. 14 are three jurisdictionalenterprises; namely, a USA Enterprise A, a UK Enterprise B, and an APACEnterprise C. Also shown in FIG. 14 are four data centers; namely, DataCenter 1 and Data Center 2 in the USA, Data Center 3 in the UK and DataCenter 4 in APAC.

Privacy and data security regulations prevent data from being exportedfrom one jurisdiction to another. In order to enforce these regulations,system 600 includes a rights manager 610 that blocks access to a datacenter by an enterprise if data export is regulations restrict datatransfer between their respective jurisdictions. Thus rights manager 610blocks access by Enterprise A to Data Centers 3 and 4, blocks access byEnterprise B to Data Centers 1,2 and 4, and blocks access by EnterpriseC to Data Centers 1, 2, and 3. Enterprises A, B and C may be commonlyowned, but access of the data centers by the enterprises is neverthelessblocked, in order to comply with data export regulations.

In accordance with an embodiment of the present invention, whenconfiguring a virtual protection group, an administrator may set aterritory/data center restriction. When the administrator subsequentlyselects a destination resource for data replication for a virtualprotection group, system 600 verifies that the resource is located in ageography that does not violate a territory/data center restriction.

The present invention may be implemented through an applicationprogramming interface (API), exposed as web service operations.Reference is made to Appendices I-V, which define an API for virtualreplication web services, in accordance with an embodiment of thepresent invention.

It will thus be appreciated that the present invention provides manyadvantages, including inter alia:

-   -   heterogeneous hypervisor replication, for different types of        sources and target hypervisor; e.g., from a VMWARE® hypervisor        to a XEN® hypervisor;    -   heterogeneous storage replication, for different types of        storage systems; e.g., from an EMC® storage system to a NETAPP®        storage systems;    -   bi-directional replication, whereby one enterprise may replicate        from the enterprise to a cloud data center, while another        enterprise simultaneously replicates from a cloud data center        back to the enterprise; and    -   security, whereby the cloud infrastructure is not exposed.

Aspects of the present invention provide disaster recovery systems withcalendar-based, or date and time-based, RPO objectives and bandwidthallocations, thereby achieving greater flexibility and costeffectiveness vis-à-vis conventional single-RPO systems.

Using the present invention, a disaster recovery system may share a linkbetween sites for replication and applications, and effectively copewith varying application change rates. The disaster recovery system mayset a higher RPO objective during peak times and a lower RPO objectiveduring off-peal times, limit data replication bandwidth during peaktimes, and relax data replication bandwidth during off-peak times. Thedisaster recovery system may use the different RPO objectives toadvantage for allowing as much bandwidth as possible for production,taking into account that a higher RPO objective is met during peaktimes, while catching up afterwards during off-peak times when the RPOobjective is lower.

Conversely, the disaster recovery system may set a lower RPO objectiveduring peak times and a higher RPO objective during off-peak times, toenable sharing the link with other systems during off-peak times.

In accordance with an embodiment of the present invention, a controlelement is installed, to control bandwidth at a site level, protectiongroup level. The control element monitors RPO objective in accordancewith a calendar-based, or a date and time-based schedule.

In accordance with an embodiment of the present invention, a disasterrecovery system may set different limits for data seeding traffics vs.data replication traffic over a WAN.

Reference is made to FIG. 15, which is a screen shot of a multi-RPOconsole for a disaster recovery application, in accordance with anembodiment of the present invention. The data recovery policy shown inFIG. 15 designates four timeframes, each timeframe having its own RPOobjective and bandwidth limitation. The timeframes are scheduled using aweekly calendar. Timeframe 1 corresponds to 12:00 AM-4:00 AM, Mon.-Sun.Timeframe 2 corresponds to 4:00 AM-8:00 AM, Mon.-Thurs. Timeframe 4corresponds to 8:00 AM-2:00 PM, Mon.-Fri. and 2:00 PM-6:00 PM,Mon.-Thurs. Timeframe 3 corresponds to the remainder of the week.

Reference is made to FIG. 16, which is a simplified block diagram of anexemplary multi-RPO data protection system, in accordance with anembodiment of the present invention. Shown in FIG. 16 are a protectedsite 700 and a replication site 800. Protected site 700 includes avCenter server 710, ESX/ESXi hypervisors 720 and 730, and physical disks740, 750 and 760. Server 710 includes a virtual manager 715. Hypervisor720 includes virtual machines 721,722 and 723, and hypervisor 730includes virtual machines 731, 732 and 733. Hypervisors 720 and 730 alsoinclude respective virtual replication appliances 725 and 735. Physicaldisk 740 includes virtual disks 741 and 742, physical disk 750 includesvirtual disks 751 and 752, and physical disk 760 includes virtual disks761 and 762. Physical disks 740, 750 and 760 may be heterogeneous; e.g.,physical disk 740 may be a NETAPP® disk, physical disk 750 may be anIBM® disk, and physical disk 760 may be an EMC²® disk.

Replication site 800 includes a vCenter server 810, an ESX/ESXihypervisor 820, and physical disks 840 and 850. Server 810 includes avirtual manager 815. Hypervisor 820 includes virtual machines 821, 822and 823. Hypervisor 820 also includes a virtual replication appliance825. Physical disk 840 includes virtual disks 841 and 842, and physicaldisk 850 includes virtual disks 851 and 852. Physical disks 840 and 850may be heterogeneous; e.g., physical disk 840 may be a NETAPP® disk, andphysical disk 850 may be an EMC²® disk.

Reference is made to FIG. 17, which is a simplified flow diagram of amethod for multi-RPO data protection, in accordance with an embodimentof the present invention. At operation 1010 virtual manager 715 accessesa calendar-based schedule of RPO objectives and corresponding bandwidthallocations. At operation 1020 virtual manager 715 retrieves thedesignated RPO for a virtual protection group and the designatedbandwidth allocation, for a given date and time, in accordance with theschedule. At operation 1030 virtual manager 715 limits bandwidth usageof a disaster recovery system for replicating data for the virtualprotection group, based on the retrieved designated bandwidthallocation. At operation 1040 virtual manager 715 determines the currentRPO for the virtual protection group.

At operation 1050 virtual manager 715 determines whether or not thecurrent RPO, determined at operation 1040, exceeds the designated RPOretrieved at operation 1020. If so, then at operation 1060 virtualmanager 715 issues a virtual protection group RPO alert. Otherwise, atoperation 1070, virtual manager 715 turns off the virtual protectiongroup RPO alert.

In an embodiment of the present invention, virtual manager 715 isoperative to adjust the schedule of RPO objectives and correspondingbandwidth allocations in response to having issued multiple RPO alertsat operation 1060.

An RPO alert is a notification to an operator, generally indicating adata replication write rate that is too high relative to a bandwidthconstraint, which in turn means that there is a service level agreementissue or risk to be addressed. For conventional disaster recoverysystems, because of the difference between peak and off-peak data writedemands, some RPO alerts are expected, and represent warnings that canbe ignored, and other RPO alerts are not expected and represent seriousconcerns—which is generally confusing to the operator.

By using the present invention to schedule RPO objectives in accordancewith peak and off-peak write demand times, ignorable RPO alerts areavoided, and the operator knows that the RPO alerts that are issuedrepresent serious concerns that need to be addressed.

In the foregoing specification, the invention has been described withreference to specific exemplary embodiments thereof. It will, however,be evident that various modifications and changes may be made to thespecific exemplary embodiments without departing from the broader spiritand scope of the invention as set forth in the appended claims.Accordingly, the specification and drawings are to be regarded in anillustrative rather than a restrictive sense.

APPENDIX I

Site Controller Web Services

These web services include methods and properties for pairing andun-pairing sites, and for managing site details.

Properties

-   -   PeerSiteIdentifier

This property is a globally unique identifier for the peer site of agiven site.

-   -   SiteConnectionParameters

This property includes parameters to access a site, including

-   -   string Hostname—the host name or IP address of the site; and    -   int Port—the port for the virtual data services appliances at        the site.    -   SiteIdentifier

This property is a globally unique identifier for a site.

-   -   SiteManagementDetails

This property includes a name, location and contact information for asite, including

-   -   string ContactInfo—the information used to contact an        administrator in case recovery is required;    -   string Location—the location of the site; and    -   string SiteName—the name of the site.    -   ThisSiteIdentifier

This property indicates the globally unique identifier for the localsite.

Methods

-   -   GetPeerConnectionParameters

-   public SiteConnectionParameters Get PeerConnectionParameters( )

This method retrieves the IP address and port of the site paired with agiven site.

-   -   GetSiteDetails

-   public SiteDetails GetSiteDetails(SiteIdentifier siteIdentifier)

This method retrieves site details, including inter alia the IP addressand port of a designated server.

-   -   GetSiteManagementDetails

-   public SiteManagementDetails GetSiteManagementDetails(SiteIdentifier    siteIdentifier)

This method retrieves the name, location and contact informationspecified by an administrator for a designated site.

-   -   GetSiteMappings

-   public IEnumerable<SiteMapping> GetSiteMappings( )

This method retrieves the identifiers for a site and for its pairedsite.

-   -   Get TcpPort

-   public int GetTcpPort(SiteIdentifier siteIdentifier)

This method retrieves the TCP port to access the virtual data servicesapplication for a designated site.

-   -   GetUsername

-   public string GetUsername( )

This method retrieves the username for a hypervisor.

-   -   GetIP

-   public string GetIP( )

This method retrieves the IP address or a hostname for a hypervisor.

-   -   IsPaired

-   public bool IsPaired( )

This method returns true if the local site is paired with another site.Otherwise, it returns false.

-   -   Pair

-   public void Pair(SiteConnectionParameters peerConnectionParameters)

This method pairs a local site with another site.

-   -   Reconfigure

-   public void Reconfigure(String hostname, String username, String    password)

This method reconfigures hypervisor information.

-   -   SetTcpPort

-   public int SetTcpPort (SiteIdentifier siteIdentifier, int port)

This method sets the TCP port used to access the virtual data servicesappliances at a designated site.

-   -   Unpair

-   public void Unpair ( )

This method un-pairs a local and remote site.

APPENDIX II

Host Controller Web Services

These web services include methods and properties to identifyhypervisors, and to deploy virtual data services appliances onhypervisors.

Properties

-   -   HostIdentifier

This property identifies a hypervisor, and includes

-   -   string InternalHostName—a name used to identify the hypervisor;        and    -   ServerIdentifier serverIdentifier—the globally unique identifier        for the hypervisor.        Methods    -   GetCurrentlyInstallingHosts

-   public HostIdentifier GetCurrentlyInstallingHosts(SiteIdentifier    siteIdentifier)

This method retrieves a list of hypervisors where a virtual dataservices appliance is in the process of being installed, at a designatedsite.

-   -   GetCurrentlyRemovingHosts

-   public HostIdentifier GetCurrentlyRemovingHosts(SiteIdentifier    siteIdentifier)

This method retrieves a list of hypervisors where a virtual dataservices appliance is in the process of being un-deployed, at adesignated site.

-   -   GetInstalledHosts

-   public HostIdentifier GetInstalledHosts(SiteIdentifier    siteIdentifier)

This method retrieves a list of hypervisors where a virtual dataservices appliance is installed, at a designated site.

-   -   GetUninstalledHosts

-   public HostIdentifier GetUninstalledHosts( SiteIdentifier    siteIdentifier)

This method retrieves a list of hypervisors where a virtual dataservices appliance is not installed, at a designated site.

-   -   InstallVdsaOnHost

-   public CommandTaskIdentifier InstallVdsaOnHost(SiteIdentifier    siteIdentifier, HostIdentifier hostIdentifier, DatastoreIdentifier    datastoreIdentifier, NetworkIdentifier networkIdentifier, VdsaIpConf    vdsaIpConf)

This method deploys a virtual data services appliance on a specifiedhypervisor at a designated site, in accordance with a specifieddatastore, a specified type of network, and access details includinginter alia an IP a subnet mask and gateway for the VDSA.

-   -   UninstallVdsaFromHost

-   public void UninstallVdsaFromHost(SiteIdentifier siteIdentifier,    HostIdentifier hostIdentifier)

This method un-deploys a virtual data services appliance from aspecified hypervisor, at a designated site.

APPENDIX III

Protection Group Controller Web Services

These web services include methods and properties to manage virtualprotection groups.

Properties

-   -   Checkpoint

This property identifies a checkpoint by an unsigned integer.

-   -   FailoverTestInfo

This property includes information returned from a failover test,including

-   -   DateTime StartTime—The time the test started, represented as a        date and time of day;    -   DateTime EndTime—The time the test ended, represented as a date        and time of day;    -   TestStatus Status—A status of the test, including Unknown,        FailedBySystem, AbortedByFailoverCommand, AbortedBySystem,        FailedByUser, Success, CurrentlyRunning;    -   string Summary—a summary of the test;    -   string AttachmentName—a name of an attachment; and    -   byte [ ] Attachment—a key to an attachment.    -   ProtectionGroupIdentifier

This property is a globally unique identifier for a virtual protectiongroup.

-   -   ProtectionGroupManagementSettings

This property defines settings for a protection group, including

-   -   ProtectionGroupSettings—properties for a protection group;    -   vAppManagementSettings—properties for a virtual application,        when the virtual protection group protects a virtual        application; and    -   VSManagementSettings—properties for the virtual server.    -   ProtectionGroupSettings

This property defines settings for a virtual protection group, including

-   -   string Name—a name used to identify the virtual protection        group;    -   unsigned int RpoInSeconds—the maximum number of seconds between        checkpoints;    -   unsigned long LogVolumeMaxSizeInSectors—the maximum log size;    -   unsigned int LogBacklogInMinutes—the time during which log        entries are kept in cache;    -   bool UseCompression—set to true if data should be compressed        when transmitted to the peer site;    -   ProtectionGroupDefaults Defaults—defaults used to identify the        recovery site, including the IP address of the hypervisor host,        the name of the datastore, and the networks to use for tests and        for failovers    -   ProtectionGroupPriority Priority—the priority assigned to the        virtual protection group; namely, Low, Medium or High;    -   int RemoteId—the identifier assigned to the peer site; and    -   int MaxTestIntervalInMinutes—the maximum time, in minutes,        between tests.    -   ProtectionGroupStatus

This property indicates the status of a virtual protection group, fromamong Protecting, NeedReverseConfiguration, Promoting,PromotingAndNeedReverseConfiguration, Test, Failover,PromotionCompleteMirrorsNotYetActivated, MissingConfiguration,PromotingAndMissingConfiguration, RemoveInProgress.

-   -   vAppManagementSettings

This property indicates settings for a virtual application, including

-   -   vAppIdentifier        -   string InternalVAppName—a name for the virtual application;            and        -   ServerIdentifier serverIdentifier—a globally unique            identifier for the virtual application; and    -   vAppSettings        -   string InternalName—a name of the virtual application            replication destination;        -   ServerIdentifier serverIdentifier—a globally unique            identifier for the virtual application replication            destination; and        -   Type—the type of server hosting the virtual application at            the destination; namely, host(0) or cluster(1).    -   VSManagementSettings

This property indicates settings for a virtual server, including

-   -   VSIdentifier        -   string InternalVSName—a name given to the virtual server;            and        -   ServerIdentifier serverIdentifier—a globally unique            identifier for the virtual server;    -   VSSettings        -   ReplicationDestination—the destination name, identifier and            type (host/cluster) and the datastore name and identifier;            and        -   VSDestinationFolders—a failover destination folder and a            failover test destination folder, including a name and an            identifier;    -   VNicManagementSettingsCollection—virtual NIC settings; and    -   VolumeManagementSettings—settings that identify a volume, such        as the directory, path and name of the disk and type of disk,        such as a raw drive, and whether or not it is a swap disk.        Methods    -   bCheckpointsExist

-   public bool bCheckpointsExist(ProtectionGroupIdentifier identifier)

This method returns true if checkpoints exit for a designated virtualprotection group.

-   -   ClearSite

-   public CommandTaskIdentifier ClearSite(SiteIdentifier site)

This method removes the virtual protection groups defined at adesignated site.

-   -   CreateProtectionGroup

-   public CommandTaskIdentifier    CreateProtectionGroup(ProtectionGroupManagementSettings    managementSettings SiteIdentifier siteIdentifier)

This method creates a virtual protection group at a designated site.

-   -   FailOver

-   public CommandTaskIdentifier FailOver(ProtectionGroupIdentifier    identifier, CheckpointIdentifier checkpoint,    ProtectionGroupManagementSettings postFailoverSettings)

This method performs a failover of the virtual servers in a designatedvirtual protection group, to a designated checkpoint instance or to thelatest checkpoint.

-   -   FailOverTest

-   public CommandTaskIdentifier FailOverTest(ProtectionGroupIdentifier    identifier, CheckpointIdentifier checkpoint)

This method performs a failover of the virtual servers in a designatedvirtual protection group, to a designated checkpoint or to the latestcheckpoint, without creating reverse replication and without stoppingprotection of the virtual servers in the designated virtual protectiongroup.

-   -   ForceRemoveProtectionGroup

-   public CommandTaskIdentifier    ForceRemoveProtectionGroup(ProtectionGroupIdentifier identifier)

This method removes a virtual protection group irrespective of the stateof the group. This method is used if the RemoveProtectionGroup method isunable to complete successfully.

-   -   ForceUpdateProtectionGroup

-   public CommandTaskIdentifier    ForceUpdateProtectionGroup(ProtectionGroupIdentifier identifier,    ProtectionGroupManagementSettings managementSettings)

This method updates virtual protection group settings, including removalof virtual servers and disks that should have been removed using theRemoveProtectionGroup method. This method is used if theUpdateProtectionGroup method is unable to complete successfully.

-   -   GetCheckpointList

-   public List<Checkpoint> GetCheckpointList(ProtectionGroupIdentifier    identifier)

This method retrieves a list of checkpoints for a specified virtualprotection group.

-   -   GetFailOverTestInfo

-   public List<FailoverTestInfo>    GetFailoverTestInfo(ProtectionGroupIdentifier identifier, int    numOfTests)

This method retrieves information about failover tests for a specifiedvirtual protection group.

-   -   GetProtectionGroupDefaultReverseSettings

-   public ProtectionGroupManagementSettings

-   GetProtectionGroupDefaultReverseSettings(ProtectionGroupIdentifier    identifier)

This method retrieves the virtual protection group settings for aspecified virtual protection group, for use as default values forreverse replication.

-   -   GetProtectionGroupManagementSettings

-   public ProtectionGroupManagementSettings

-   GetProtectionGroupManagementSettings(ProtectionGroupIdentifier    identifier)

This method retrieves the settings for a designated virtual protectiongroup.

-   -   GetProtectionGroups

-   public IEnumerable<ProtectionGroupIdentifiers> GetProtectionGroups(    )

This method retrieves a list of virtual protection groups.

-   -   GetProtectionGroupState

-   public ProtectionGroupState    GetProtectionGroupState(ProtectionGroupIdentifier identifier)

This method retrieves the state of a specified virtual protection group,the state being “protected” or “recovered”. If the group is protected, 0is returned; and if the group is recovered, 1 is returned.

-   -   GetProtectionGroupStatus

-   public ProtectionGroupStatus    GetProtectionGroupStatus(ProtectionGroupIdentifier identifier)

This method retrieves the status of a specified virtual protectiongroup, the status being inter alia “protecting”, “testing” or“promoting”.

-   -   InsertTaggedCheckpoint

-   public CommandTaskIdentifier    InsertTaggedCheckpoint(ProtectionGroupIdentifier identifier, string    tag)

This method inserts a named checkpoint for a designated virtualprotection group. The method returns immediately, without verifyingwhether or not the checkpoint was successfully written to the journal inthe peer site.

-   -   IsPairConnected

-   public bool IsPairConnected( )

This method returns true if the connection to the paired site is up.

-   -   Move

-   public ComamndTaskIdentifier Move(ProtectionGroupIdentifier    identifier, ProtectionGroupManagementSettings postMoveSettings)

This method migrates a specified virtual protection group to the peersite.

-   -   ProtectVS

-   public CommandTaskIdentifier ProtectVS(ProtectionGroupIdentifier    identifier, VSManagementSettings vsManagementSettings)

This method adds a designated virtual server to a virtual protectiongroup, in accordance with designated settings.

-   -   RemoveProtectionGroup

-   public CommandTaskIdentifier    RemoveProtectionGroup(ProtectionGroupIdentifier identifier)

This method removes a virtual protection group, unless the group isbeing replicated during a test failover or an actual failover, andunless the group is being migrated to the peer site. If this method doesnot return a Success completion code, the ForceRemoveProtectionGroupmethod may be used to force removal of the group.

-   -   StopFailOverTest

-   public CommandTaskIdentifier    StopFailOverTest(ProtectionGroupIdentifier identifier,    FailoverTestInfo testInfo)

This method stops a failover test, and removes the test virtual serversfrom the peer site.

-   -   TrimOldFailoverTest

-   public void TrimOldFailoverTest(ProtectionGroupIdentifier    identifier, int numOfOldTestsToTrim)

This method discards information about a specified number of oldfailover tests for a designated virtual protection group, from theoldest test to the most recent test.

-   -   UnprotectVS

-   public CommandTaskIdentifier UnprotectVS(ProtectionGroupIdentifier    identifier, VSIdentifier vsIdentifier)

This method removes a designated virtual server from a designatedvirtual protection group.

-   -   UpdateProtectionGroup

-   public CommandTaskIdentifier    UpdateProtectionGroup(ProtectionGroupIdentifier identifier,    ProtectionGroupManagementSettings managementSettings)

This method updates settings of a specified virtual protection group. Ifthe method does not return a Success completion code, theForceUpdateProtectionGroup method can be used to force the update.

-   -   WaitForCheckpoint

-   public CommandTaskIdentifier    WaitForCheckpoint(ProtectionGroupIdentifier identifier, Checkpoint    checkpoint, int waitingIntervalInSeconds, int timeoutInSeconds)

This method waits for a checkpoint to be written to a journal on thepeer site, after it was inserted, or times out if it takes too long.

APPENDIX IV

Command Tracker Web Services

These web services include methods and properties to monitor proceduresbeing executed.

Properties

-   -   CommandTaskInfoProperties

This property includes.

-   -   enum CommandType—valid methods;    -   enum CompletionCode—the result of running a method, including        NotAvailable, Success, Aborted, Failed and HadException;    -   int OriginalInputParms—input parameters; and    -   int PgId—the globally unique identifier for a virtual protection        group.        Methods    -   GetAllTasks

-   public List<CommandTaskIdentifier> GetAllTasks( )

This method retrieves a list of all tasks that are currently active.

-   -   Get CompletionCode

-   public CommandTaskCompletionCode    GetCompetionCode(CommandTaskIdentifier taskid)

This method returns the completion code of a specified task. Completioncodes include Success, Aborted, Failed or HadException. If the task isstill running, NotAvailable is returned.

-   -   GetCommandTaskInfo

-   public CommandTaskInfo GetCommandTaskInfo(CommandTaskIdentifier    cmdIdentifier)

This method returns the command type, the completion code inputparameters, and the virtual protection group identifier of a designatedtask.

-   -   GetExceptionString

-   public string GetExceptionString(CommandTaskIdentifier taskId)

This method returns the string associated with an exception, for adesignated task that had an exception. The method GetCompletionCodereturns HadException if a task had an exception.

-   -   GetProgress

-   public int GetProgress (CommandTaskIdentifier taskid)

This method returns progress as a percentage of a whole task, as aninteger, for a specified task.

-   -   GetProtectionGroupCommandTaskid

public CommandTaskIdentifierGetProtectionGroupCommandTaskId(ProtectionGroupIdentifier pgId)

This method returns the identifier of a task currently being performedon a designated protection group.

-   -   GetProtectionGroupCommandTaskidLocally

-   public CommandTaskIdentifier    GetProtectionGroupCommandTaskIdLocally(ProtectionGroupIdentifier    pgId)

This method returns the identifier of a task currently being performedon a specified protection group at a local site.

-   -   GetResult

-   public Object GetResult(CommandTaskIdentifier taskId)

This commend returns the result for a designated task. The returnedresult may be one of the following:

-   -   the identifier of the virtual protection group identified by the        task ID;    -   the settings of the virtual protection group identified by the        task ID;    -   a checkpoint whose insertion is identified by the task ID; or    -   the identifier of the log collection identified by the task ID.    -   GetStatus

-   public CommandTaskStatus GetStatus(CommandTaskIdentifier taskId)

This method retrieves the current status of a specified task. The statusmay be Active, Running, Aborted or Completed.

-   -   Wait

-   public void CommandTaskIdentifier Wait(ComamndTaskIdentifier taskId,    int IntervalInMillis, int TimeOutInMillis)

This method waits for a specified task to complete, by polling the taskat specified time intervals, until a specified time out.

APPENDIX V

-   -   Log Collector Web Services

These web services include methods and properties to retrieveinformation for troubleshooting.

Properties

-   -   LogCollectionRequest

This property indicates details of a log request, including a level ofdetail of information, indicating whether information about a virtualdata service appliance and core information should be included, andincluding start and end times for the information.

Methods

-   -   CollectSystemLogs

-   public CommandTaskIdentifier CollectSystemLogs(LogCollectionRequest    request)

This method initiates a log request.

-   -   RetrieveLogPackage

-   public Stream RetrieveLogPackage (LogCollectionIdentifier id)

This method retrieves results of a log request.

What is claimed is:
 1. A system for disaster recovery, comprising: acontroller for a server having at least one processor, the controllerhaving a virtual manager configured to cause the at least one processorto manage at least one hypervisor and to cause the at least oneprocessor to: (i) control bandwidth usage of a disaster recovery systemin accordance with a plurality of recovery point objectives (RPOs), eachof the plurality of RPOs designating a maximal time loss constraint fordata recovery for an enterprise production system, wherein theenterprise production system includes a hypervisor system comprisingmultiple virtual protection groups, and a corresponding bandwidthallocation for the disaster recovery system to use in replicating datafor the enterprise production system, wherein each of the plurality ofRPOs are applied in accordance with a calendar-based schedule of datesand times, wherein multiple calendar-based schedules are used toschedule each of the RPOs and bandwidth allocations to control issuanceof RPO alerts and the bandwidth usage for data replication for acorresponding virtual protection group of the enterprise productionsystem, and (ii) issue an RPO alert when the maximal time lossconstraint for a current date and time for one of the plurality of RPOsis not satisfied when the maximal time loss constraint exceeds abandwidth constraint.
 2. The system of claim 1 wherein bandwidth isshared between the disaster recovery system and the enterpriseproduction system, and wherein the bandwidth allocation for each RPO isan allocation of the shared bandwidth.
 3. The system of claim 2, whereinthe calendar-based schedule allocates more bandwidth to the disasterrecovery system during off-peak production times for the enterpriseproduction system, and allocates less bandwidth to the disaster recoverysystem during peak production times for the enterprise productionsystem.
 4. The system of claim 1 wherein said controller adjusts thecalendar-based schedule in response to having issued multiple RPOalerts.
 5. A method for disaster recovery, comprising: accessing acalendar-based schedule of a plurality of recovery point objectives(RPOs) and corresponding bandwidth allocations for a disaster recoverysystem, each RPO of the plurality of RPOs designating a maximal timeloss constraint for data recovery for an enterprise production system,wherein the enterprise production system includes a hypervisor systemcomprising multiple virtual protection groups, and each bandwidthallocation constraining bandwidth usage for replicating data for theenterprise production system, wherein multiple calendar-based schedulesare used to schedule each of the RPOs and bandwidth allocations tocontrol issuance of RPO alerts and the bandwidth usage for datareplication for a corresponding virtual protection group of theenterprise production system; retrieving, by the disaster recoverysystem at any given date and time, the recovery point objective (RPO)and the corresponding bandwidth allocation for the given date and time,from the calendar-based schedule; limiting, by the disaster recoverysystem at the given date and time, bandwidth usage of the disasterrecovery system in accordance with the retrieved bandwidth allocation;determining, by the disaster recovery system, a current RPO; andissuing, by the disaster recovery system, an RPO alert based on thecurrent RPO exceeding the retrieved RPO.
 6. The method of claim 5wherein bandwidth is shared between the disaster recovery system and theenterprise production system, and wherein the bandwidth allocation foreach RPO is an allocation of the shared bandwidth.
 7. The method ofclaim 6, wherein the calendar-based schedule allocates more bandwidth tothe disaster recovery system during off-peak production times for theenterprise production system, and allocates less bandwidth to thedisaster recovery system during peak production times for the enterpriseproduction system.
 8. The method of claim 5 further comprising adjustingthe calendar-based schedule in response to multiple occurrences of saidissuing an RPO alert.
 9. The system of claim 1, wherein the controllerreduces a data replication rate for the enterprise production systemduring off-peak production times.
 10. The system of claim 1, wherein thecontroller increases a data replication rate for the enterpriseproduction system during peak production times.
 11. The system of claim1, wherein the controller reduces an RPO objective for the enterpriseproduction system during off-peak production times.
 12. The system ofclaim 1, wherein the controller increases an RPO objective for theenterprise production system during peak production times.
 13. Thesystem of claim 1, wherein the controller establishes at least fourtimeframes for a weekly calendar schedule, wherein each of the at leastfour timeframes has a unique RPO objective and bandwidth limit.
 14. Thesystem of claim 2, wherein the controller reduces an RPO objective forthe enterprise production system during peak production times andincreases an RPO objective for the enterprise production system duringoff-peak production times to enable the enterprise production system toshare bandwidth with the disaster recovery system.
 15. The method ofclaim 5, comprising: reducing a data replication rate for the enterpriseproduction system during off-peak production times.
 16. The method ofclaim 5, comprising: increasing a data replication rate for theenterprise production system during peak production times.
 17. Themethod of claim 5, comprising: reducing an RPO objective for theenterprise production system during off-peak production times.
 18. Themethod of claim 5, comprising: increasing an RPO objective for theenterprise production system during peak production times.
 19. Themethod of claim 5, comprising: establishing at least four timeframes fora weekly calendar schedule, wherein each of the at least four timeframeshas a unique RPO objective and bandwidth limit.
 20. The method of 6,comprising: reducing an RPO objective for the enterprise productionsystem during peak production times and increasing an RPO objective forthe enterprise production system during off-peak production times toenable the enterprise production system to share bandwidth with thedisaster recovery system.